<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .container {
            height: 150px;
            background-color: pink;
            margin: 0 auto;
        }

        /* 超小屏幕下  屏幕小于768 布局容器宽度设置为100% */
        @media screen and (max-width:767px) {
            .container {
                width: 100%;
            }
        }

        /* 小屏幕下 屏幕大于768，布局容器改为750px */
        @media screen and (min-width:768px) {
            .container {
                width: 750px;
            }
        }

        /* 中等屏幕大于992，布局容器改为970px */
        @media screen and (min-width:992px) {
            .container {
                width: 970px;
            }
        }

        /* 大屏幕大于1200，布局容器改为1170px */
        @media screen and (min-width:1200px) {
            .container {
                width: 1170px;
            }
        }
    </style>
</head>

<body>
    <!-- 响应式布局开发里面,首先需要一个布局容器 -->
    <div class="container">

    </div>
</body>

</html>